Mounting seat for an integrated circuit and a circuit board and method of manufacturing the same

ABSTRACT

A mounting seat for an integrated circuit (IC) and a circuit board includes a base formed by way of powder metallurgy, two pin holes formed on the base, and two positioning pins, which may be respectively formed in the pin holes by way of insert molding or inserted into the pin holes by way of assembling. Thus, a surface of the base may be quickly molded to form the positioning pins or assembled with the positioning pins, which are made of a material different from that of the base. Consequently, the method of manufacturing the mounting seat is simple and timesaving, and the manufacturing cost can be reduced.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a mounting seat for an integratedcircuit (IC) and a circuit board, and more particularly to a mountingseat for mounting a digital micromirror device (DMD) made by MEMStechnology and a circuit board.

2. Prior Art

A typical mounting seat for an integrated circuit (IC) or amicroprocessor is a block-like body, and a surface of the mounting seatis formed with a plurality of terminal holes. The mounting seat isadhered onto a surface of a circuit board, and electrical connectionpoints of the mounting seat are electrically connected to circuits ofthe circuit board. The IC or microprocessor has protruding terminals,which are inserted into the terminal holes of the mounting seat. Thus,the IC or the microprocessor can be electrically connected to thecircuits of the circuit board.

In addition, MEMS devices have been widely used in digital imageproducts such as projectors, digital televisions, and the like. Forexample, Texas Instruments Incorporated has proposed a digitalmicromirror device (DMD), which has made using the MEMS technology, inconjunction with the digital light processing (DLP) to constitute theoptical architecture of a projector.

The DMD has to be placed on a mounting seat, on which a circuit board tobe electrically connected to the DMD is disposed. For example, U.S. Pat.No. 6,894,853 discloses a micromirror device, which is disposed on asurface of a ceramic seat, and a printed circuit board is adhered to theother surface of the ceramic seat. The micromirror device iselectrically connected to the circuit board through a plurality ofwires. In the '853 patent, the mounting seat is only adhered to thecircuit board without any pre-positioning design, so the mounting seatand the circuit board have to be aligned precisely.

FIG. 1 shows another assembled structure of a mounting seat and acircuit board according to the prior art. As shown in FIG. 1, twoopposite positioning pins 12 are formed on a mounting seat 10. Thepositioning pins 12 and the mounting seat 10 are integrally formed. Twopositioning holes 16 of a circuit board 14 correspond to the twopositioning pins 12. The circuit board 14 can be positioned firmly bycombining the positioning pins 12 with the positioning holes 16.

As shown in FIG. 2, the positioning pin 12 has a small outer diameterand cannot be easily formed by way of powder metallurgy. So, a shafthaving a larger outer diameter is firstly formed, and then the shaft iscut or milled to remove a portion of the outer circumference 18(indicated by dashed lines) of the shaft so that a pin having a smallerradius is obtained. The method of forming the positioning pin 12 is veryinconvenient and requires a longer period of time to finish the cuttingand milling processes. So, it is disadvantageous to the mass production.Meanwhile, the manufacturing cost is high because the extra machiningprocedures are needed.

The positioning pins 12 of the mounting seat 10 and the circuit board 14are simply positioned. Thus, it is unnecessary to form the positioningpins 12 with the high-precision powder metallurgy method and the cuttingor milling processes. In other words, modifying the method of formingthe positioning pins and the structure configuration under the conditionof the positioning requirement is advantageous to the improvement of thedifficulty in manufacturing the mounting seat and the elimination of thedrawback of the high cost.

SUMMARY OF THE INVENTION

According to the above-described prior art, the base and the positioningpins of the prior art mounting seat are integrally formed by the samematerial, so the mounting seat cannot be manufactured easily and has ahigh cost. Therefore, the invention provides a new mounting seat tosolve the prior art problems.

An object of the invention is to provide a method of manufacturing amounting seat for an IC and a circuit board. The method includes thesteps of: forming a base by way of powder metallurgy and forming two pinholes on the base; and placing the base in a mold and forming twopositioning pins protruding beyond a surface of the base in the pinholes by way of insert molding. The positioning pins may be made of aplastic material or a Bakelite material, so the pins may have smallerouter diameters. Thus, the mounting seat does not need the prior artcutting or milling processes, and thus can be manufactured more easilywith the lower manufacturing cost.

Another object of the invention is to provide a method of manufacturinga mounting seat for an IC and a circuit board. The method includes thesteps of: forming a base by way of powder metallurgy and forming two pinholes on the base; forming two positioning pins separated from the baseby way of injection molding; and assembling the positioning pins withthe base by inserting the positioning pins into the pin holesrespectively, wherein one end of each of the positioning pins protrudesbeyond a surface of the base. The positioning pins may be made of aplastic material or a Bakelite material, so the pins may have smallerouter diameters. Thus, the mounting seat does not need the prior artcutting or milling processes, and thus can be manufactured more easilywith the lower manufacturing cost.

Still another object of the invention is to provide a mounting seat foran IC and a circuit board. The mounting seat includes a base, two pinholes formed on the base and at two opposite ends of the base, and twopositioning pins each having a first end and a second end. The firstends of the positioning pins are fixed into the two pin holes,respectively, and the second ends of the positioning pins protrudebeyond a surface of the base. Thus, the inconvenience of machining thepositioning pins can be eliminated, and the manufacturing cost can begreatly reduced.

Other objects, features, and advantages of the invention will becomeapparent from the following detailed description of the preferred butnon-limiting embodiments. The following description is made withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view showing a mounting seat and a circuit boardaccording to the prior art.

FIG. 2 shows the exterior of the conventional positioning pin before andafter it is machined.

FIG. 3 shows the exterior of a base according to the invention.

FIG. 4 is a schematic illustration showing a positioning pinmanufactured by way of insert molding according to the invention.

FIG. 5 is an exploded view showing the positioning pin and the basewhich are assembled together according to the invention.

FIG. 6 is a schematic illustration showing an assembled structure of thepositioning pin and the base according to the invention.

FIG. 7 is a block diagram showing a manufacturing method according tothe invention.

FIG. 8 is a block diagram showing another manufacturing method accordingto the invention.

FIG. 9 is an exploded view showing the mounting seat and the circuitboard according to the invention.

FIG. 10 is a schematic illustration showing an assembly of the mountingseat, the circuit board and an IC device according to the invention.

FIG. 11 partially shows the exterior of the mounting seat according tothe invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 3 shows a base 22 of a mounting seat 20. The base 22 is made by wayof powder metallurgy. A surface of the base 22 is formed with two pinholes 23 and an accommodating opening 24. A heat sink 26 is disposed onthe surface of the base 22. The two pin holes 23 are disposed atopposite ends. The accommodating opening 24 is formed at a middleposition of the base 22, and the heat sink 26 crosses over two sides ofthe accommodating opening 24 and protrudes beyond the surface of thebase 22.

As shown in FIG. 4, the base 22 is placed in an injection molding mold90, and a positioning pin 30 is formed in each pin hole 23 by way ofmolding. Thus, the positioning pin 30 and the base 22 are combinedtogether.

It is to be noted that the positioning pin 30 is formed in the pin hole23 by way of insert molding. The positioning pin 30 may be formed of,without limitation to, a plastic material or a Bakelite material.

As shown in FIG. 5, the base 22 of the mounting seat 20 is formed by wayof powder metallurgy. The surface of the base 22 is formed with two pinholes 23 and one accommodating opening 24, and a heat sink 26 isdisposed on the surface of the base. The two pin holes 23 are disposedat two opposite ends. The accommodating opening 24 is formed at a middleposition of the base 22. The heat sink 26 crosses over two sides of theaccommodating opening 24 and protrudes beyond the surface of the base22. Also, two positioning pins 40 may be formed by any method, such asinjection molding, and the material thereof may be the plastic materialor the Bakelite material.

As shown in FIGS. 5 and 6, the two positioning pins 40 corresponding tothe pin holes 23 are inserted into and fixed to the pin holes 23,respectively. Consequently, the positioning pins 40 and the base 22 arecombined together. The process of combining the positioning pins 40 withthe base 22 may be performed by an automating apparatus.

As shown in FIG. 7, the method of the invention includes steps 52 and54.

In step 52, the base having two pin holes is formed by way of powdermetallurgy.

In step 54, the base is placed in an injection molding mold, and thepositioning pin, which protrudes beyond the surface of the base, isformed in each pin hole by way of insert molding.

After steps 52 and 54 are finished, the mounting seat may be taken outand used.

As shown in FIG. 8, another method of the invention includes steps 52,56 and 58.

In step 52, the base having two pin holes is formed by way of powdermetallurgy.

In step 56, the positioning pins are formed by way of any moldingtechnology (e.g., by way of injection molding technology).

In step 58, the positioning pins are assembled into and adhered to thepin holes of the base. The assembling process may be performed quicklyby an automating apparatus.

In the above-mentioned manufacturing methods of the invention, eitherthe method of forming the positioning pin 30 in the pin hole 23 by wayof insert molding technology or the method of inserting and assemblingthe separately formed positioning pins 40 into the pin holes 23 canquickly finish the manufacturing procedures without additional machiningprocedures. Thus, the manufacturing cost can be effectively reduced.

As shown in FIG. 9, the mounting seat 20 mentioned hereinabove includesa base 22, two pin hole 23 and one accommodating opening 24 formed onthe surface of the base 22, and one heat sink 26 disposed on the surfaceof the base 22. The two pin holes 23 are formed at two opposite ends.The accommodating opening 24 is formed at a middle position of the base22, and the heat sink 26 crosses over two sides of the accommodatingopening 24 and protrudes beyond the surface of the base 22. As shown inFIGS. 9 and 11, two positioning pins 30 are assembled in the pin holes23, and the edge of the positioning pin 30 is formed with a ring-shapedguiding slant 32.

As shown in FIGS. 9 and 10, when a circuit board 60 is to be disposed onthe mounting seat 20, positioning holes 62 of the circuit board 60correspond to the positioning pins 30, respectively. The circuit board60 and the positioning pin 30 can be easily combined together under theguiding of the guiding slant 32 with respect to the positioning hole 62.The circuit board 60 is placed on the surface of the base 22 and theeffects of adhering and positioning can be achieved.

Also, an IC (or a MEMS device) 70 is disposed in the accommodatingopening 24, a surface of the IC 70 contacts the heat sink 26, which isadvantageous to the heat dissipation. Consequently, the structure of theinvention enables the IC 70 and the circuit board 60 to be assembled andpositioned on the mounting seat 20 easily, and also enhances the heatdissipation efficiency.

While the preferred embodiment of the present invention has been shownand described, it will be apparent to those skilled in the art thatvarious modifications may be made in the embodiment without departingfrom the spirit of the present invention. Such modifications are allwithin the scope of the present invention.

1. A method of manufacturing a mounting seat for an integrated circuit(IC) and a circuit board, the method comprising the steps of: forming abase by way of powder metallurgy and forming two pin holes on the base;and placing the base in a mold and forming two positioning pinsprotruding beyond a surface of the base in the pin holes by way ofinjection molding.
 2. The method according to claim 1, wherein thepositioning pins are formed by way of insert molding.
 3. The methodaccording to claim 1, wherein the positioning pins are made of a plasticmaterial or a Bakelite material.
 4. A method of manufacturing a mountingseat for an integrated circuit (IC) and a circuit board, the methodcomprising the steps of: forming a base by way of powder metallurgy andforming two pin holes on the base; forming two positioning pinsseparated from the base by way of injection molding; and assembling thepositioning pins with the base by inserting the positioning pins intothe pin holes respectively, wherein one end of each of the positioningpins protrudes beyond a surface of the base.
 5. The method according toclaim 4, wherein the positioning pins are made of a plastic material ora Bakelite material.
 6. A mounting seat for an integrated circuit (IC)and a circuit board, the mounting seat comprising: a base; two pin holesformed on the base and at two opposite ends of the base; and twopositioning pins each having a first end and a second end, wherein thefirst ends of the positioning pins are fixed into the two pin holes,respectively, and the second ends of the positioning pins protrudebeyond a surface of the base.
 7. The mounting seat according to claim 6,wherein the pin holes penetrate through the mounting seat.
 8. Themounting seat according to claim 6, wherein the second end of thepositioning pin is formed with a guiding slant at a circumference of thepositioning pin.
 9. The mounting seat according to claim 6, wherein thepositioning pin is adhered to the pin hole.
 10. The mounting seataccording to claim 6, wherein the positioning pin is fixed into the pinhole by way of insert molding.
 11. The mounting seat according to claim6, wherein the surface of the base is formed with an accommodatingopening for accommodating the IC.
 12. The mounting seat according toclaim 6, wherein a protruding heat sink is disposed on the surface ofthe base.
 13. The mounting seat according to claim 6, wherein thesurface of the base is formed with an accommodating opening and a heatsink is disposed on the surface of the base, and the heat sink crossesover two sides of the accommodating opening and protrudes beyond thesurface of the base.